22.01.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Ye. R. Baisalov: On countably categorical graphs

29.01.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

M.I. Bekenov: On model companions of uncountably categorical theories

12.02.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov: On pseudofinite acyclic graph theories

19.03.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov: On pseudofinite acyclic graph theories (продолжение)

26.02.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

День проблем! (на основе https://www.forkinganddividing.com/)

04.03.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov: On pseudofinite abelian group theories 

11.02.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

День проблем! (на основе https://www.forkinganddividing.com/)

18.03.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov:  Mustafin T.G. On similarities of complete theories (article abstracting)

1.04.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov:  Mustafin T.G. On similarities of complete theories (article abstracting, continuation)

8.04.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

N.D. Markhabatov:  Mustafin T.G. On similarities of complete theories (article abstracting, continuation)

15.04.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Ye. R. Baisalov: Nurtazin A.T. Countably categorical graphs with finitely many chains (article abstracting)

22.04.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Ye. R. Baisalov: Nurtazin A.T. Countably categorical graphs with finitely many chains (article abstracting, continuation)

13.05.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Nuraly Adilkhan: Fraisse Construction (abstracting)

20.05.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Nuraly Adilkhan: Fraisse Construction (abstracting, continuation)

27.05.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Mamyrov Assylkhan: Hrushovskii Construction (abstracting)

03.06.2024, 16.00-18.00 MMF (ЦИСИ) room 224 

Mamyrov Assylkhan: Hrushovskii Construction (abstracting, continuation)

18.10.2024, 17.00-18.00 MMF (ЦИСИ) room 224 

A.R.Yeshkeev: Some properties of Jonsson theories

12.11.2025, 18.00-19.00 MMF (ЦИСИ) room 209 

Fazyl Jebei: Alternatives for pseudofinite groups (https://arxiv.org/pdf/1205.3533 ) 

14.01.2026, 11.00-12.00 MMF (ЦИСИ) room 115 

Fazyl Jebei: Direct Products, Ultraproducts, and Model-Theoretic Properties of Abelian Groups 

14.01.2026, 12.00-13.00 MMF (ЦИСИ) room 115 

Mahsut I. Bekenov: On the properties of elementary embeddability

20.01.2026, 16.00-17.00 MMF (ЦИСИ) room 305

Kyle Gannon: When do groups recognize coordinates?

Abstract: Suppose that G is a group and I is an infinite index set. Then one can easily construct automorphisms from \prod_{i \in I} G to itself by permuting indices and choosing an indexed family of automorphism from G to itself. However, the natural question then arrises: when does every automorphism of \prod_{i \in I} G essentially decompose into the form described above? In general, we are interested in when classes of groups have such property with respect to all (reduced) products. Using model theoretic methods, one can show that certain natural families of groups have such property and that a total characterization is quite complicated. This is joint work with Ilijas Farah and Pierre Touchard. 

27.01.2026, 16.00-17.00 MMF (ЦИСИ) room 305

Nikolay A. Bazhenov: On primitive recursive reverse mathematics

Abstract: Reverse mathematics is a research program, which dates back to the 1970s, whose goal is to determine the exact axiomatic strength of theorems from different areas of mathematics. It deals with statements about countable (or countably presentable) structures, using the framework of the formal system of second-order arithmetic Z_2. In recent years, there has been much work in primitive recursive (also called 'punctual') algebra. Motivated by these developments, we investigate the proof-theoretic strength of theorems over the system PRA^2 (i.e., the second-order primitive recursive arithmetic). We give an overview of some recent results concerning theorems in algebra, analysis, and infinite combinatorics. This is joint work with Marta Fiori-Carones, Lu Liu, and Alexander Melnikov.

02.02.2026, 16.00-18.00 MMF (ЦИСИ) room 305

Aliya M.  Mamyraly: Some properties of elementary embeddabilaty in the model theory

Abstract: The properties of elementary embedding in model theory and the influence of the spectral function B_T(\lambda, \mu) on theoretical characteristics are investigated. This function calculates the number of classes partitioned by the \lambda-similarity relation of models, allowing for the determination of the theory's completeness, model completeness, and categoricity. Specifically, it is shown that the condition B_T(\lambda, \mu) = 1 is directly related to the theory being categorical in uncountable powers and its overall completeness. It is proven that the condition  B_T(\lambda, \mu) = 1 holds if and only if the algebraic system of classes formed by elementary embedding is isomorphic to the set of cardinal numbers with a linear order.

Furthermore, the differences between the number of non-isomorphic models I_T and the values of the spectral function B_T are demonstrated using Ehrenfeucht theories and specially constructed sets of models. For instance, cases are identified where the number of non-isomorphic models reaches continuum cardinality, I_T(\omega) = 2^\omega, while the value of the spectral function remains countable, B_T(\omega, \omega) = \omega. These results highlight that the spectral function provides a more concise structural characterization of theories compared to traditional isomorphism-based classifications. 

Based on Bekenov, M.I. Properties of Elementary Embeddability in Model Theory. J Math Sci 230, 10–13 (2018). https://doi.org/10.1007/s10958-018-3721-4

09.02.2026, 16.00-18.00 MMF (ЦИСИ) room 305

Fazyl G. Zhebey: On the Structure of Saturated Elementary Extensions of Direct Sums of Cyclic Groups